The objective of our research is to obtain a quantitative and fundamental physicochemical understanding of the interactions of immune complexes and other serum components with various immunoadsorbents. Our aims are to: (1) understand the complex interactions in solution involving antigen, antibody, complement, and other plasma-borne molecules; (2) define the reactions in solution between immune complexes and various receptor molecules that bind immunoglobulins, immune complexes, and/or complement components; and (3) investigate the reactions occurring during immunosorption of immune complexes with a variety of receptor molecules (e.g., protein A, bovine conglutinum, human Cl[unreadable]q[unreadable]) bound to solid supports. Our objectives for the coming year include: (1) complete physicochemical and immunological characterization of monoclonal and polyclonal antibodies under study including, where applicable, determination of affinity constants, hydraulic radius, isoelectric point, and epitope specificity; (2) further studies of IC size formation and redistribution using SDGC and QLS with monoclonal Abs and low-moderate affinity polyclonal Ab preparations; (3) development of mathematical models describing IC formation between bivalent Abs and multivalent Ags for comparison with our experimental results; (4) further analysis of naturally occurring IC, including separation of IC into their constituent components, characterization of all components, and determination of average apparent association constants of the respective Abs and Ags; (5) construction of a minielectrophoresis cell that will allow QLS spectroscopy on IC as they move within an electric field; and (6) preparation of a variety of immunoadsorbents including immobilized protein A, conglutinin, and Cl[unreadable]q[unreadable] for studies during the third year on the effects of immunoadsorption on physicochemical properties of IC. (HF)